Effects of grain size and temperature on mechanical response of nanocrystalline copper

Molecular dynamics simulation is utilized to study the effects of grain size and temperature on the mechanical properties of quasi-two-dimensional (2D) nanocrystalline Cu with grain sizes of 3-8 nm under uniaxial tensile tests. Our results show that the grain growth is caused by the grain rotation and leads to strain hardening at 300 K for a grain size of <5 nm and at 100 K for a grain size of <4 nm. For a grain size of ≤7 nm, the inverse Hall-Petch relation was observed in the yield stress. The Young's modulus for the quasi-2D system is higher than that for the three-dimensional (3D) system.